Lapping tool



Dec. 16, 1947. R. BRoE 2,432,606

LAPPING TOOL Filed April 16, 1947 y A@ j@ y@ Patented Dec. 16, 1947 UNITED STATES PATENT OFFICE LAPPING TOOL Roy Broe, Oak Park, Ill. Application April 16, 1947, Serial No. 741,785

7 Claims.

The invention relates to lapping tools for pol' ishing o-r honing the bores for cylinders, or holes in metal parts.

One object of the invention is to provide a lapping tool which is simple in construction, can be inexpensively fabricated, is eicient in operation, and in Iwhich parts can be readily replaced.

Other objects of the invention will appear rom the detailed description.

The invention consists in the several novel features hereinafter set forth, and more particularly dened by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation of a lapping tool embodying the invention.

Fig. 2 is a longitudinal section taken on line Z-,-2 of Fig. 3.

Fig. 3 is a longitudinal section taken on line 3'3 of Fig. 2.

Fig. 4 is a longitudinal section taken on line l-li of Fig. 3.

Fig. 5 is a separate detail of the spring for spreading the segmental lapping elements.

The invention is exemplied in a one-piece mandrel which comprises a shank I0 and a rigid integral body or head Il which is provided with a cylindrical periphery I2. Diametrically opposite longitudinal channels Ill, extend from end to end of and are cut in the body I I. A pair of lapping elements I6 and I'I are formed of sheet metal, are arcuate in cross-section and have inner peripheries conforming substantially to the cylindrical periphery I2 of the body II. The outer periphery of segments I6 and II, are usually provided with grooves for distributing the lapping compound around said periphery. Segments I 6 and Il are provided with longitudinal inturned flanges I8 which extend radially inward into the channels I@ for limiting the radially outward or spreading movement of the segments on the mandrel body I I. The inner edges of flanges are slidable on the bottoms of the channels, and the sides of said channels are normally engaged by the anges. A slot 2i] extends diametrically through the body I@ and intersects the outer end of said body. Head i I is provided adjacent its inner end with a circumferential shoulder-forming groove 2l and the inner ends of segments I6 and Il are peened or indented as at 22, into groove 2|, for holding the segments on and against outward longitudinal removal from head II. A spring generally designated 24 is confined in slot 20 and resiliently engages the segments I 6 and Il for spreading or pressing them radially outward against the wall of the hole or cylinder being lapped. When the tool is free, the spring spreads the segments within the limits permitted by the flanges I8 in channels lli. Spring 24 is preferably formed of a strip of resilient metal or wire and includes outer members 25 which extend 1ongitudinally of and engage the segments and an inner longitudinally extending connecting loop between members 25. The outer terminals 21 of members 25 are bent outwardly to engage the inner peripheries of the segments adjacent their outer ends, and the bends 23 at the inner ends of the spring and between members 25 and 26, are adapted to engage the inner periphery of the segments.

In the operation of the lapping tool, the segments I6 and Il are contractible around the body I I in the bore or hole in which the tool is inserted against the spreading force of spring 24, which presses the outer periphery of the segments against the work. The spring 2li oats in the slot 20 so that it permits either end of the segments to be contracted or pressed together or expanded independently of each other, or both ends to be compressed or expanded so that the outer periph.. ery of the segments may conform to the irregularities in the hole or bore during the lapping or honing of the tool.

A characteristic of the invention is, that the tool is composed of parts which can be readily fabricated and assembled. The segments can be formed with dies and the grooves I4 and slot 20 may be readily cut or machined in the body II. Spring 24 can be inserted endwise into the slot 20, and the segments may be readily secured on the head by indenting their inner ends to intert With the annular groove 2i in head II. When it is desirable or necessary to replace the segments on account of wear, it is only necessary to release the indented portions 22 outwardly, whereupon the segments can be removed endwise from the head. In assembling the segments and the head, it is only necessary to indent the segments.

The invention exemplies a lapping tool which is simple in construction, can be inexpensively fabricated, and is elicient in operation,

The invention is not to be understood as limited to the details described, since these may be modifled within the scope of the appended claims without departing from the spirit or scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. A lapping tool comprising a mandrel including a rigid body provided with a longitudinal slot extending diametrically through the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of sheet metal, extending circumferentially and 1ongitudinally around the outer iace of the body and having integral means extending inwardly into the channels for limiting the radially outward movement of the segments, and spring means confined in the slot and between the segments for yieldingly spreading them.

2. A lapping tool comprising a mandrel including a rigid one-piece body provided with a longitudinal slot extending diametrically through the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of sheet metal, extending circum-Y ferentially and longitudinally around the outer face of the body and having integral inturned anges extending into the channels for limiting the radially outward movement of the segments, and spring means coniined in the slot and between the segments for yieldingly spreading them.

3. A lapping tool comprising a mandrel in cluding a rigid one-piece body provided with a longitudinal slot extending diametrically through the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of sheet metaly extending circumferentially and longitudinally around the periphery of the body and having integral means extending inwardly into the channels for limiting the radially outward movement of the segments, spring means confined in the slot and between the segments for yieldingly spreading them, and means integral with the body and the segments for holding the segments longitudinally on the body.

4. A lapping tool comprising a mandrel including a rigid one-piece body provided with a longitudinal slot extending diametrically through the body and intersecting the outer end of the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of sheet metal, extending circumferentially and longitudinally around the periphery of the body and having inturned integral ilanges extending into the channels for limitingithe radially outward movement of the segments, spring means confined in the slot and between the segments for yieldingly urging them radially outward, the body being provided with a groove at the inner end of the segments, and means integral with the segments extending into said groove for holding the segments longitudinally on the body.

5. A lapping tool comprising a mandrel including a rigid body provided with a longitudinal slot extending diametrically through the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of sheet metal, extending circumferentially and 'longitudinally around the outer face of the body and having means extending inwardly into the channels for limiting the radially outward movement of the segments, and spring-means includv ing members extending longitudinally of the slot and engaging the segments for yieldingly spread` ing them outward.

6. A lapping tool comprising a mandrel including a rigid body provided with a longitudinal slot extending diametrically through the body and with longitudinal channels in the outer face of the mandrel, arcuate lapping segments formed of 'sheet metal, extending circumferentially and longitudinally around the outer face of the body and having means extending inwardly into the channels for limiting the radially outward movement of the segments, and a resilient strip including members extending substantially from end to end of the slot and engaging the segments for yieldingly spreading them.

'7. A lapping tool comprising a mandrel including a shank and a rigid one-piece body, the body being provided with a Straight cylindrical periphery, a longitudinal slot extending diametrically through and open at the outer end of the body and with longitudinal channels in the periphery and open at the outer end of the body, arcuate lapping segments,`formed of sheet metal, extending longitudinally and circumferentially of the body and having inturned longitudinal anges extending into the channels for limiting the radially outward movement of the segments, and a Spring insertable endwise into the slot and including members extending longitudinally of the slot and engaging the segments for urging them radially outward.

ROY BROE. 

